C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,g,sm;
	cin>>a>>b;
	if(a<b){
		sm=a;
	}else{
		sm=b;
	}
	for(int i=1;i<=sm;i++){
		if(a%i==0&&b%i==0)g=i;
	}
	cout<<g<<endl;
	return 0;	
}

Python :

# coding=utf-8
m = int(input())
n = int(input())
s = 1
for i in range(2, n):
    if (n % i == 0 and m % i == 0):
        s = (s * i)
        m = (m / i)
        n = (n / i)
        while (n % i == 0 and m % i == 0):
            s = (s * i)
            m = (m / i)
            n = (n / i)
print(s)